在connectionDidFinishLoading中收到錯誤，EXC_BAD_ACCESS

Question

我在執行NSURLConnection委託方法connectionDidFinishLoading時收到錯誤。有趣的是，它可以在模擬器上運行，但它在物理設備上崩潰。更有趣的是它崩潰，只有當這種操作序列完成後，

• 運行應用程序
• 顯示資料Tweet！ （真棒）
• 按Home鍵
• 雙擊Home鍵
• 強制退出應用程序
• 再次打開應用
• CRASHED !!!!! （:(）...保持崩潰，直到你重新啓動手機

錯誤日誌：

Exception Type: EXC_BAD_ACCESS (SIGSEGV) 
Exception Codes: KERN_INVALID_ADDRESS at 0xa0000008 
Crashed Thread: 0 

Thread 0 name: Dispatch queue: com.apple.main-thread 
Thread 0 Crashed: 
0 libobjc.A.dylib     0x321befbc 0x321bb000 + 16316 
1 Tittle-Tattle     0x0002cf10 -[MapViewController connectionDidFinishLoading:] (MapViewController.m:108) 
2 Foundation      0x3316bc32 0x330a5000 + 814130 
3 Foundation      0x330c36e2 0x330a5000 + 124642 
4 Foundation      0x330c36ac 0x330a5000 + 124588 
5 Foundation      0x330c35ce 0x330a5000 + 124366 
6 CFNetwork      0x35e7689e 0x35e67000 + 63646 
7 CFNetwork      0x35e6b53e 0x35e67000 + 17726 
8 CFNetwork      0x35e6b632 0x35e67000 + 17970 
9 CFNetwork      0x35e6b23c 0x35e67000 + 16956 
10 CFNetwork      0x35e6b172 0x35e67000 + 16754 
11 CoreFoundation     0x34176afc 0x340e9000 + 580348 
12 CoreFoundation     0x341762c8 0x340e9000 + 578248 
13 CoreFoundation     0x3417506e 0x340e9000 + 573550 
14 CoreFoundation     0x340f84d6 0x340e9000 + 62678 
15 CoreFoundation     0x340f839e 0x340e9000 + 62366 
16 GraphicsServices    0x3254dfc6 0x3254a000 + 16326 
17 UIKit       0x3734e73c 0x3731d000 + 202556 
18 Tittle-Tattle     0x000200e0 main (main.m:16) 
19 Tittle-Tattle     0x00020084 start + 32 

CODE：

- (void)connectionDidFinishLoading:(NSURLConnection *)connection { 

    [urlConnection cancel]; 
    [urlConnection release]; 
    NSString *responseString = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding]; 

    //Since we got new fresh data we shall put it in LatestLocationData entity in CoreData 
    [self insertLastKnownLocationDataIntoCoreDataWith:responseString]; 

    //Test purpose only, See what we have got in CoreData 
    [self fetchLastKnownLocationDataFromCoreData]; 

    NSDictionary *results = [responseString JSONValue]; 
    placesNearBy = [results objectForKey:@"results"]; 

    [responseString release]; 

    [self dropNearByPlacesAnnotationsFrom:placesNearBy]; 

} 

問：什麼可能是可能的原因是什麼？

類似的問題（！不是由我）以前提出的，但對這個問題沒有人回答說：Application not running in iOS 5

---

據我瞭解到目前爲止，只有EXE_BAD_ACCESS當您試圖訪問還沒有內存地址發生已被分配，或先前已分配但現在已被釋放。

修改回覆IN後評論：

嘿Firoze，這是怎麼了初始化NSURLConnection的

urlConnection = [[NSURLConnection alloc] initWithRequest:request delegate:self]; 

Answer 1

在您的意見看，我建議你使用@property聲明對所有高德的。他們將減輕你所要做的所有手動內存管理，這可能是你的問題所在。

簡單的例子

YourClass.h

@interface YourClass 
@property (nonatomic, retain) NSURLConnection *urlConnection; 
// More ivars 

// Method declations 
@end 

YourClass.m

@interface YourClass 

@synthesize urlConnection = _urlConnection; 

// The method where you instantiate urlConnection 
{ 
    NSURLConnection *urlConnection = [[NSURLConnection alloc] initWithRequest:request 
                    delegate:self]; 
    self.urlConnection = urlConnection; 
    [urlConnection release]; urlConnection = nil; 

    // Do whatever else you do here 
} 

- (void)connectionDidFinishLoading:(NSURLConnection *)connection 
{ 
    [self.urlConnection cancel]; 
    self.urlConnection = nil;  <- This takes care of releasing the ivar and setting it to nil so there is no dangerous hanging pointer 

    // ... the rest of your method 
} 

[urlConnection cancel]; 
[urlConnection release]; 
// You need to clean up after yourself with any ivars you make 
- (void)dealloc 
{ 
    [_urlConnection release]; 
    // Release any other ivars 
    [super dealloc]; 
} 
@end